地球内核中的微型异质性在地球内核中的微型异质性
1Earth and Space Science Department and Institute of Geophysics and Planetary Physics, University of California at Los Angeles, 90095-1567, USA. vidale@ucla.edu
Nature
|April 5, 2000
概括
地震波散射揭示了地球固体内核的刚度变化. 这些发现表明,核心的外层内构成或异构的潜在变化.
科学领域:
- 地质物理学 地质物理学
- 地震学 地震学
- 地球科学 地球科学 地球科学
背景情况:
- 地球内核的地震性质对于了解其组成和热状态至关重要.
- 异位性和速度异质性表明内核生长和对流.
- 内核中的高地震波衰减归因于散射或内在衰减.
研究的目的:
- 为了研究地球内核内的地震波散射.
- 分析到达预期反射时间的分散地震波的特征.
- 根据散射幅度推断内核最外层的特性.
主要方法:
- 在内核中分散的地震波的观测.
- 从内核边界对地震体波反射的分析.
- 模拟分散波幅以确定刚度变化.
主要成果:
- 观测到分散的地震波与内核边界的体波反射一致.
- 分散的波幅由硬度变化1.2%解释,尺度长度为2公里.
- 这些变化位于内核最外围的300公里内.
结论:
- 内核最外围的300公里表现出显著的硬度变化.
- 这些变化可能表明成分变化,部分融化或地震异构.
- 散射分析为内核的结构和动态提供了新的见解.
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